Micro-electro-mechanical structures (MEMS) integrate electrical elements with mechanical elements on a micro scale using mircofabrication. The integration of mechanical elements with electrical elements allows for the creation of a complete system on a chip, such that the electronics of a chip may physically interact with the external environment. MEMS are often formed utilizing processes similar to those used to fabricate traditional CMOS integrated circuits, such as the formation and removal of material layers to form components of a device. The use of similar formation processes allows MEMS structures to be created using integrated circuit manufacturing facilities and equipment, allowing the creation of, for example, microphones, gyroscopes, accelerometers, and micro inkjet heads that are integrated with CMOS circuits on a single chip. Similar to integrated circuit manufacturing, MEMS are typically formed in bulk processes on a semiconductor wafer.
MEMS often utilize metal/ceramic layers to form interconnections between a MEMS device on a semiconductor wafer, other MEMS devices on the semiconductor wafer, and integrated circuits on the semiconductor wafer; metal/ceramic layers are also used for adhesion layers, strengthening layers, and buffer layers. The metal/ceramic layers are typically formed with a sputtering process after the formation of the MEMS devices. A person of ordinary skill in the art will recognize that metal/ceramic layers formed with a sputtering process will exhibit CVD-like deposition in which a layer is formed on horizontal surfaces that is thicker than the layer formed on vertical surfaces, such as the sidewall of variable topography MEMS structures. Thus, when variable topography exists on the surface of the wafer structures, the resultant metal/ceramic layers are thin along the sidewalls of changes in the surface topography.
As a result of the thin sidewall metal/ceramic layers, cracks in the metal/ceramic layers often form at changes in the surface topography, i.e., in corner regions. The cracks hinder the ability of the metal/ceramic layers to perform their intended function, often resulting in locations of high resistance and a lack of structural support. Therefore, there is a need for a system and/or method for forming the metal/ceramic layers.